1. Field of the Invention
The present invention relates to a method of manufacturing a nonvolatile storage device.
2. Description of the Related Art
Recently, a semiconductor storage device of a resistance change type (resistive random access memory (ReRAM)) that stores information making use of a change in a resistance of a variable resistance element attracts attention. In the ReRAM, a memory cell array is formed by vertically providing columnar structures (pillars), which are formed by laminating variable resistance elements and diodes, at cross points of bit lines and word lines. A reduction in a pitch of the pillars is necessary to advance refining of the ReRAM.
As a technology for the pitch reduction, a sidewall transfer technology for forming a line and space pattern is put to practical use. In the sidewall transfer technology, so-called loop-cut is necessary as treatment of an end of a reduced pitch region. Such treatment of an end could cause a problem in reducing a pitch of the pillars. No technology for reducing a pitch of the pillars is put to practical use. As a method of forming holes in a reduced pitch that are reversed patterns of the pillars, there is a technology proposed in Japanese Patent Application Laid-Open No. 2009-4535. However, the end treatment is not taken into account in this technology.